(3-H)-dihydrotestosterone in catecholamine neurons of rat brain stem: combined localization by autoradiography and formaldehyde-induced fluorescence.

A combined formaldehyde-induced fluorescence (FIF)-autoradiography procedure was used to determine how and where the androgen, dihydrotestosterone (DHT), is associated with catecholamine systems in the rat brain. With this dual localization method, (3H)-DHT target sites can be visualized in relation to catecholamine perikarya and terminals. In the hindbrain, catecholamine neurons adjacent to the fourth ventricle (group A4), the nucleus (n.) olivaris superior (group A5), the n. parabranchialis medialis (group A7), and in the locus coeruleus (group A6) and subcoeruleal regions, as well as in the substantia grisea centralis, concentrate (3H)-DHT in their nuclei. (3H)-DHT target neurons appear to be innervated by numerous catecholamine terminals in the following hindbrain regions: n. motorius dorsalis nervi vagi, n. tractus solitarii, n. commissuralis, n. raphe pallidus, n. olivaris inferior, the ventrolateral portion of the substantia grisea centralis, n. cuneiformis, and the ventrolateral reticular formation in the caudal mesencephalon. In the forebrain, (3H)-DHT concentrates in nuclei of catecholamine neurons located in the n. arcuatus and n. periventricularis (group A12). In addition, (3H)-DHT target neurons appear to be innervated by numerous catecholamine terminals in the following forebrain regions: n. periventricularis rotundocellularis, n. paraventricularis, n. dorsomedialis, n. periventricularis, area retrochiasmatica, n. interstititalis striae terminalis (ventral portion), and n. amygdaloideus centralis. The disclosure of a morphologic association between (3H)-DHT target sites and certain brain catecholamine systems suggests a close functional interdependence between androgens and catecholamines.